"The Bajau deliberately rupture their eardrums at an early age."

From a story about the "sea nomads" of the Malaysian region:

Diana is one of the world's last marine nomads; a member of the Bajau ethnic group, a Malay people who have lived at sea for centuries, plying a tract of ocean between the Philippines, Malaysia and Indonesia...

They are highly skilled free divers, plunging to depths of 30m and more to hunt pelagic fish or search for pearls and sea cucumbers – a delicacy among the Bajau and a commodity they have traded for centuries.

Since diving is an everyday activity, the Bajau deliberately rupture their eardrums at an early age. "You bleed from your ears and nose, and you have to spend a week lying down because of the dizziness," says Imran Lahassan, of the community of Torosiaje in North Sulawesi, Indonesia. "After that you can dive without pain." Unsurprisingly, most older Bajau are hard of hearing. 

The rest of the article is decidedly downbeat:

These days, those who can afford it dive using compressors. Air is pumped through a garden hose so divers can go deeper for longer – 40m or more. Unaware of the need to restrict their exposure to pressure, countless Bajau have ended up crippled or killed by deadly nitrogen bubbles in their bloodstream.

The practice continues, however, because it's lucrative – especially when potassium cyanide is involved. Cyanide fishing was first introduced in the Philippines by Hong Kong fishing boats looking for reef species such as grouper and Napoleon wrasse to satisfy seafood restaurants' rising demand for live fish...

Torosiaje used to be flanked by teeming reefs; now there are only wastelands of broken coral, the legacy of years of dynamite and cyanide fishing. It's a common story throughout the Coral Triangle – communities destroying the environment that sustains them, driven by voracious global markets.

Additional information (and pix) at the Guardian source.  Photo by James Morgan (gallery here).